Open coil annealing



Oct. 25, 1966 R. c. PLATE 3,281,290

OPEN COIL ANNEALING Original Filed Aug. 31, 1961 l/VI/E/VTOR RA YMO/VD6. PLATE Attorney United States Patent Office 3,281,290 Patented Oct.25, 1966 3,281,290 OPEN COIL ANNEALING Raymond C. Plate, Monroeville,Pa., assignor to United States Steel Corporation, a corporation ofDelaware Continuation of application Ser. No. 135,214, Aug. 31, 1961.This application Mar. 9, 1964, Ser. No. 351,281 1 Claim. (Cl. 148134)This application, which is a continuation of my copending applicationSerial No. 135,214, filed August 31, 1961, now abandoned, relates toopen coil annealing and more particularly to a method of annealing coilsof steel strip with a particular type of separator therein. Open coilannealing is described in an article by Arnold in the August 1960 issueof Iron and Steel Engineer and also in an article by Bausher in the May1961 issue of Iron and Steel Engineer. The usual practice in open coilannealing is to place a nylon cord between the convolutions of the coilto separate the same and then remove the cord before annealing the coilof strip. Since the nylon cord has to be removed from the coil before itis placed in the furnace for annealing, uniform spacing of theconvolutions of the coil is not assured. For this reason other types ofseparator elements have been suggested, but none of these have provedsatisfactory for various reasons. For example, some become crushed inuse so that they cannot be reused. This also prevents adequatecirculation of the atmosphere gas. Others are of such shape that theycannot provide for adequate circulation of the atmosphere gas. In somecases the materials used were such that they could not readily be woundon a spool for handling.

It is therefore an object of my invention to provide a method ofannealing coils of strip in which the separator remains in the coilduring the annealing cycle and can be readily removed and prepared forreuse.

This and other objects will be more apparent after referring to thefollowing specification and attached drawings, in which:

FIGURE 1 is a schematic plan view of apparatus suitable for placing theseparator in position in a coil;

FIGURE 2 is a schematic view showing a coil in an annealing furnace;

FIGURE 3 is an enlarged view taken on the line III-III of FIGURE 2; and

FIGURE 4 is a view taken on the line IVIV of FIG- URE 3.

Referring more particularly to the drawings, reference numeral 2indicates a rotatable table for receiving a tight wound coil of strip C.A rotatable table 4 is provided in spaced apart relationship to table 2for supporting a loose coil C of strip. A separator removal boom 6 maybe located above the table 4. An unwinder 8 is provided adjacent thetable 4 for rotatably supporting a reel 10 carrying an elongatedseparator 12. The separator 12 consists of a relatively straight wire 14having a wire 16 spiraled therearound.

An annealing furnace 18 for annealing coils of strip C is shown inFIGURE 2 and basically consists of a base 20 for supporting the coil ofstrip C, a fan 22 for circulating deoxidizing gas through the coil Cwithin an inner cover 24 and an outer cover 26 surrounding the innercover 24 for providing the annealing heat. The apparatus shown inFIGURES 1 and 2 are conventional and is therefore shown schematicallywith details being omitted. The apparatus shown schematically in FIGURE1 is preferably like that shown in the Iron and Steel Engineer articlesmentioned above and the apparatus shown in FIGURE 2 can be similar tothat shown in Woodson Patent No. 2,137,869 dated November 22, 1938 andMunford Patent No. 2,546,697 dated March 27, 1951.

In making up the separator 12 the inner wire 14 may be made of lowcarbon hard drawn steel and the outer wire 16 of a softer mtaerial suchas annealed low carbon steel. However, stainless steel, which canwithstand the annealing heat without damage has proved to be verysuccessful in use. However, the straight Wire 14 should always be harderthan the outer wire 16. The diameter of outer wire 16 is preferably atleast as great as the diameter of the wire 14. The number of twists ofthe outer wire per inch may vary. For example, three or four twists perinch may be used, but this may be varied as desired to increase thespace available for circulation of the atmosphere gas. To prevent theseparator from sticking during the annealing cycle it is preferablyannealed after formation thereof.

In carrying out the method of my invention a tight coil of strip C ismounted on the tables 2 and fed therefrom to the mandrel 4C of table 4.Separator 12 from reel 10 is fed to a position above table 4 andfastened to the end of the steel strip after which the table 4 isrotated to pull the strip from the coil C so as to position theseparator 12 between the convolutions of the coil C as it is formed. Itwill be seen that spaces 28 and 30 are provided between the wire 14 andthe convolutions of strip on each side thereof. The amount of spaceavailable for such circulation of gases may be increased by increasingthe pitch of the spirals of wire 16. The coil C with the separator 14therein is removed from table 4 and placed on base 20 after which theinner cover 24 and outer cover 26 are placed thereover and heat issupplied thereto with the fan 22 circulating the atmosphere gas throughthe open convolutions of the coil. After the annealing cycle theseparator 12 may be removed from the coil C at the furnace site andrewound on a reel 10 or the coil may be returned to the table 4 and theseparator 12 removed by means of the boom 6 as described in the Iron andSteel Engineer articles.

While one embodiment of my invention has been shown and described, itwill be apparent that other adaptations and modifications may be madewithout departing from the scope of the following claim.

I claim:

In a method of annealing coils of steel strip which comprises coilingthe strip about a vertical mandrel with a separator between theconvolutions of strip, annealing the coil with the separator therein andits axis vertical wherein atmosphere gas passes between the convolutionsof the strip during annealing; the improvement comprising utillizing aseparator including a center wire the axis of which forms thelongitudinal axis of the separator, and an outer wire spiraled aboutsaid center wire over a majority of the length thereof, the number oftwists of the outer wire being a maximum of four per inch, with adjacentspirals being spaced from one another at substantially uniform pitch toprovide a space therebetween, at least one of said wires being made ofstainless steel.

References Cited by the Examiner UNITED STATES PATENTS 379,535 3/1888Hewitt 57145 (Other references on following page) UNITED STATES PATENTSFOREIGN PATENTS s l i 57 144 512,811 9/1939 Great Britain.

Lancaster 174 42 OTHER REFERENCES Peterson. 5 Blickwede: Journal ofMetals, August 1961, relied on, DAvaucourt. P

Wilson- 266-5 DAVID L. RECK, Primary Examiner.

Wilson et a1. 263-40 C. N. LOVELL, Assistant Examiner.

1. IN A METHOD OF ANNEALING COILS OF STEEL STRIP WHICH COMPRISES COILINGTHE STRIP ABOUT A VERTICAL MANDREL WITH A SEPARATOR BETWEEN THECONVOLUTIONS OF STRIP, ANNEALING THE COIL WITH THE SEPARATOR THEREIN ANDITS AXIS VERTICAL WHEREIN ATMOSPHERE GAS PASSES BETWEEN THE CONVOLUTIONSOF THE STRIP DURING ANNEALING; THE IMPROVEMENT COMPRISING UTILLIZING ASEPARATOR INCLUDING A CENTER WIRE THE AXIS OF WHIC FORMS THELONGITUDINAL AXIS OF THE SEPARATOR, AND AN OUTER WIRE SPIRALED ABOUTSAID CENTER WIRE OVER A MAJORITY OF THE LENGTH THEREOF, THE NUMBER OFTWISTS OF THE OUTER WIRE BENG A MAXIMUM OF FOUR PER INCH, WITH ADJACENTSPIRALS BEING SPACED FROM ONE ANOTHER AT SUBSTANTIALLY UNIFORM PITCH TOPROVIDE A SPACE THEREBETWEEN, AT LEAST ONE OF SAID WIRES BEING MADE OFSTAINLESS STEEL.